Electron beam apparatus and electron beam inspection method

ABSTRACT

An electron beam apparatus which includes a sample stage on which a sample is placed, and an electron optical system. The electron optical system includes an electron gun that generates a primary electron beam, an immersion objective lens that converges the primary electron beam on the sample, an ExB deflector that separates a secondary particle, which is generated from irradiation of the primary beam to the sample, from an optical axis of the primary beam, a reflecting member to which the secondary particle collides, an assist electrode which is located under the reflecting member, a plurality of incidental particle detectors that selectively detect a velocity component and an azimuth component of a ternary particle which is generated by the secondary particle colliding to the reflecting member, and a center detector that is located above the reflecting member.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/877,715, filed Oct. 24, 2007, now U.S. Pat. No. 7,875,849, thecontents of which are incorporated herein by reference.

CLAIM OF PRIORITY

The present invention claims priority from Japanese application JP2006-290772, filed on Oct. 26, 2006, the content of which is herebyincorporated by reference on to this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technology for manufacturing asubstrate comprised of a very tiny circuit pattern, such as asemiconductor devices and a liquid crystal. More particularly, thepresent invention relates to a charged-particle beam inspectiontechnology for inspecting the tiny circuit pattern using acharged-particle beam.

2. Description of the Related Art

Semiconductor devices are fabricated by repeating a step of transferringa pattern, which is formed on a wafer using a photo mask, throughlithography or etching. In such a fabrication process, for quick boostof a yield and realization of stable running of the fabrication process,it is a must to quickly analyze a defect, which is discovered byperforming in-line wafer inspection, for the purpose of taking measureson the basis of the results of the analysis. In order to link theresults of the inspection to a countermeasure to defectives, atechnology for quickly reviewing numerous detected defects andclassifying them by a cause is needed.

However, due to the decrease of a design rule of semiconductormanufacturing process, the size of a defect affecting a fabricationyield of a semiconductor device is decreasing. A conventional opticalreview apparatus has difficulty in reviewing and classifying microscopicdefects because of an insufficient resolution. Consequently, a scanningelectron microscope (SEM) type review apparatus capable of reviewingdefects at a high resolution has come to be adopted. In the reviewapparatus, acquisition of a shadow image based on an SEM image which isequivalent to a shadow caused by light incident from side of an objectto be reviewed is important in detecting a roughness such as amicroscopic foreign matter or a scratch.

A general principle for acquisition of the shadow image will bedescribed in conjunction with FIG. 1. When an roughness 1 caused by aforeign matter included in a film is scanned with an electron beam 2, asecondary particle 3 is emitted from each irradiated point on a sample.The generated secondary particle 3 has a distribution with respect tothe energy. A component of a relatively low energy (low-velocitycomponent) is referred to as a secondary electron (SE), while acomponent of a relatively high energy (high-velocity component) isreferred to as a backscattering electron (BSE). As indicated with arrows6 in FIG. 1, a secondary particle at a generational position at whichthe secondary particle is generated has elevation-angle componentsoriented in various directions. Here, the elevation angle of a secondaryparticle at a generational position means an angle formed by eachelevation-angle component of the secondary particle with respect to aplane to which the optical axis of an irradiated primary electron beamis normal. As far as a certain elevation-angle component 6 of asecondary particle at a generational position is concerned, componentsof the secondary particle emitted rightward reach a detector 4 butcomponents thereof emitted leftward do not reach the detector.Therefore, the quantity of a secondary electron detected by the detector4 varies depending on a level of a slope 5 of a sample surface at thegenerational position of a secondary particle. Consequently, a shadowcontrast depending on an roughness on a sample surface is appeared in ashadow image 7 obtained by the detector.

Disclosed in Japanese Patent Application Laid-Open No. 8-273569 is aninvention relating to a charged-particle beam column in which asecondary charged particle detection optical system using amagnetic/electrostatic compound objective lens, accuracy of measurementis improved by detecting a low-velocity component (SE) and ahigh-velocity component (BSE) in a secondary particle distinctively. Inthe invention disclosed in the publication, an annular detector disposedbetween an electron source and an objective lens is utilized, and thebackscattering electron is detected in an internal annular zone of theannular detector, and the secondary electron is detected in an externalannular zone of the annular detector, on the basis of the fact thattrajectories of the low-velocity component and high-velocity componentof a secondary particle are different, thus the separation and detectionof the secondary particle is achieved by. The external annular zone isdivided into four sectors so that a specific azimuth component of asecondary electron at a position from which the secondary electron isemitted can be distinguished. Consequently, a shadow image can beacquired.

On the other hand, disclosed in PCT Publication No. WO00/19482 is aconfiguration for distinguishing and detecting a low-angle component anda high-angle component of a secondary particle. In the inventiondisclosed in the publication, a secondary particle detector fordetecting the low-angle component is disposed above an objective lens,and a reflector to which the low-angle component of a generatedsecondary particle collides is disposed between the low-angle componentdetector and objective lens. Further, an incidental particle generatedfrom the collision of the low-angle component is introduced into thelow-angle component detection secondary particle detector using an ExBdeflector, whereby the low-angle component of a reflected electron and asecondary electron are detected. For the high-angle component of thereflected electron, another high-angle component detection secondaryparticle detector and a second ExB deflector are disposed above the ExBdeflector (on the side of the electron source) so that the high-anglecomponent detector can detect the high-angle component alone.

Moreover, disclosed in Japanese Patent Application Laid-Open No.2006-228999 is an electron microscope in which an annular detector isdisposed between an electron source and an objective lens so that alow-elevation angle component and a high-elevation angle component of agenerated secondary electron can be separated from each other and anazimuth component can be separated from the secondary electron.

SUMMARY OF THE INVENTION

A secondary particle generated from irradiation of an electron beam canbe discriminated into four types in terms of an elevation angle at thegenerational position (low-angle component and high-angle component),and an energy (high-velocity component and high-velocity component),that is, a low-angle and low-velocity component, a low-angle andhigh-velocity component, a high-angle and low-velocity component, and ahigh-angle and high-velocity component. Out of the secondary particle,the high-velocity component contains substantial information accordingto the shape of the generational position of the secondary particle. Onthe other hand, the low-velocity component contains substantialinformation according to the interior of a sample within a rangecorresponding to a penetration depth of a primary beam (for example, thematerial of the sample, the composition thereof, and so on).Consequently, if a secondary particle generated from irradiation of aprimary beam were distinguished and detected into a low-velocitycomponent and a high-velocity component in order to form an image, itwould be advantageous in observation of a sample. An image formed basedon the high-velocity component may be referred to as a shadow image.

In the conventional arts described in Japanese Patent ApplicationLaid-Open No. H8-273569, PCT Publication No. WO00/19482, and JapanesePatent Application Laid-Open No. 2006-228999, a secondary particle canbe detected in a low-angle component and a high-angle componentdistinctively. However, out of a high-velocity component of thesecondary particle, a high elevation angle component at the generationalposition of the secondary particle cannot be sufficiently separated froma low-velocity component. As a result, a shadow image lacks thehigh-velocity high-elevation angle component, and the intensity of thecontrast of the shadow image is reduced than an potentially obtainablevalue. This causes a problem that a figure with a roughness of smalldegree (shallow) does not appear in a shadow image.

Further, since only a weak contrast shadow image is obtained, image datahas to be integrated many times in order to ensure a satisfactorysignal-to-noise ratio for the image. Consequently, a qualified image forthe inspection or measurement of a sample cannot be acquired in a shorttime. If a beam current of the primary beam is increased, an imagesignal with a high signal-to-noise ratio can be obtained. However, anincrease of a beam current leads to an increase in a beam diameter,resulting degradation in the resolution of an image.

Accordingly, an object of the present invention is to provide acharged-particle beam inspection technology capable of acquiring animage in which shadow contrast is more enhanced than a conventional one,in shorter time than that required conventionally.

In the present invention, the above object is accomplished by providingtrajectory separating means for separating the trajectory of alow-velocity component and a high-energy component of a secondaryparticle each other, generated by an irradiation of a primary electronbeam. A fundamental principle for the separation of the trajectorieswill be described below.

FIG. 2 shows an energy distribution of an emission density of asecondary particle emitted from a sample. In the drawing, the verticalaxis indicates the emission density of a secondary particle, and thehorizontal axis of indicates the energy of the secondary particle. Theenergy of the secondary particle are distributed within a range from 0to a value corresponding to the energy of an irradiated primary beam(Vp). The emission density shows two peaks in the low energy side andthe high energy side, the low energy side peak 10 corresponds to asecondary electron, and the low energy side peak 11 corresponds toenergy a backscattering electron. Hereinafter, the peak 10 signifyingthe secondary electron and the peak 11 signifying the backscatteringelectron shall be regarded as the representative value of a low-velocitycomponent and a high-velocity component of a secondary particle at agenerational position of the secondary electron. Herein, as seen fromFIG. 2, since the distribution energy of the secondary electron and thedistribution energy of the backscattering electron has a tail in boththe higher and lower energy side respectively, it is impossible tostrictly discriminate the secondary electron and the backscatteringelectron from each other. Therefore, the “high-velocity component” or“low-velocity component” appeared in the following description, theysignify a distribution of secondary particle in which the peak 10 orpeak 11 is major content as shown in FIG. 2. If necessary, the term“secondary electron” or “backscattering electron” will be employed.

FIG. 3 shows the results of simulation indicating an effect of amagnetic field to a secondary electron (SE) and a backscatteringelectron (BSE) in passing through an objective lens, that is, therelationship between rotational angles of the secondary electron 20 andbackscattering electron 21 rotated by the magnetic field, and elevationangles of the secondary electron 20 and backscattering electron 21exhibits at a generational position of a secondary particle. In thedrawing, the vertical axis indicates rotational angle, and thehorizontal axis indicates elevation angle at the generational positionof a secondary particle. Because the secondary electron 20 andbackscattering electron 21 are emitted from a sample in specificdirections, each of the secondary electron 20 and backscatteringelectron 21 have proper velocity vectors at the generational position.The velocity vector can be expressed with the azimuth, elevation angle,and energy of the secondary electron 20 or backscattering electron 21.In a case of an objective lens is a lens utilizing a magnetic field, thesecondary electron 20 and backscattering electron 21 pass through theobjective lens with rotating spirally in the magnetic field. Anrotational angle caused by a magnetic field varies depending on theenergy of a secondary particle. Consequently, in a case that the degreeof rotation is large, information on an azimuth angle included in asecondary particle at the generational position thereof is lost, so thatthe discrimination of an azimuth angle component of each secondaryparticle becomes impossible. Referring to FIG. 3, in a case that theelevation angle at the generational position is the same in thesecondary electron and backscattering electron, the rotational angle ofthe secondary electron 20 is larger than that of the backscatteringelectron 21. Consequently, it is harder to enhance a shadow contrast ina secondary-electron image than that in a backscattering-electron image.

On the other hand, since the degree of the rotational angle of thebackscattering electron 21 depending on the elevation angle is smallerthan that of the secondary electron, a shadow contrast of an imageproduced based on the backscattering electron can be enhanced.Generally, the contrast of an observation image of a shallow roughnessor a tiny foreign matter is weak. If the shallow roughness is observedin a way of enhancing the shadow, newly generated contrast is added tothe shallow roughness, so that the contrast is enhanced. The newlygenerated contrast shall be referred to as a shadow contrast. Smallrotational angle of a secondary particle enables to distinguish theazimuth angle component, thus the shadow contrast increases. Thus, bydetecting a high-velocity component with a wide range in the elevationangle at a generational position, and distinguishing into the azimuthcomponent, the shadow contrast is enhanced. Consequently, the shallowroughness or tiny foreign matter can be detected with high sensitivity.

Next, referring to FIG. 4 and FIG. 5, a method for separating ahigh-velocity component of a secondary particle from a low-velocitycomponent thereof and controlling the ratio of separation will bedescribed below.

FIG. 4 shows the trajectory of a secondary particle in an electronoptical system with insufficient separation of the high-velocitycomponent and the low-velocity component of the secondary particle. Forsimplicity, the optical axis 33 of an electron beam is regarded asperpendicular to a sample 32. In facing to the sample 32, amagnetic/electrostatic compound objective lens 31 is disposed. Themagnetic/electrostatic compound objective lens 31 is composed of a coil34 and an electrode 35. The potential difference between the sample 32and electrode 35 is retained in a range from +1 kV to +50 kV. A leftreflector 36 and a right reflector 37 are disposed on a opposite side tothe sample 32 with respect to the magnetic/electrostatic compoundobjective lens 31. A left detector 42 and a right detector 43 for thebackscattering electron are disposed on both side of the left reflector36 and right reflector 37 respectively. Though not depicted, detectorfor the secondary electron is disposed above the left reflector 36 andright reflector 37. A negative voltage is applied to each of the leftreflector 36 and right reflector 37. The potential difference of theleft reflector 36 and right reflector 37 to the electrode 35 is from 0 Vto −50 kV.

A secondary particle generated by the irradiation with the primary beamis accelerated by an electric field induced by the electrode 35 inpassing through the magnetic/electrostatic compound objective lens 31.At this time, both high-angle and low-angle components of a secondaryelectron contained in a secondary particle pass through an openingformed in the reflectors. On the other hand, a low-angle component of abackscattering electron traces a trajectory 39 deviated from the opticalaxis. As to the high-angle component of the backscattering electron, thehigh-angle component passes through the opening in the reflectors beforesufficiently moving on an XY plane (that is, without spreading thetrajectory to lateral direction), because the backscattering electronhas originally high energy (that is, a high velocity). In other words,the high-velocity component of the backscattering electron is notdetected by the backscattering electron detectors 42 and 43, whichshould detect the high-velocity component potentially. Further, in thecase that the trajectory 38 of the low-angle component of the secondaryelectron is coincide with the trajectory 40 of the high-angle componentof the backscattering electron, the separation of the secondary electronand the backscattering electron becomes impossible.

On the other hand, a backscattering electron collided to the leftreflector 36 and right reflector 37 generates a re-emission secondaryelectron 41. The re-emission secondary electron 41 is detected by boththe left detector 42 and right detector 43. Part of the re-emissionsecondary electron 41 is attracted by the electrode 35 and may thereforenot be detected.

In a conventional electron optical system, a secondary particle thatlost the high-elevation angle component 40 of a backscattering electronand part of the re-emission secondary electron 41 finally reaches toeach detector. As a result, a shadow contrast of an image which isformed based on signals sent from the left and right detectors 42 and 43cannot be enhanced.

FIG. 5 shows the trajectory of a secondary particle in an electronoptical system equipped with separation means for the high-velocitycomponent and a low-velocity component of a secondary particle, moreparticularly, equipped with a trajectory separating means for asecondary electron and the backscattering electron. In a description ofFIG. 5, the components having a same function as in FIG. 4 will beomitted. In the electron optical system shown in FIG. 5, as thetrajectory separating means for the secondary electron and thebackscattering electron, an assist electrode 50 surrounding annularlythe optical axis 59 of a primary electron beam is interposed betweenmagnetic/electrostatic compound objective lens 51 and a pair of left andright reflectors 52 and 53. A voltage approximately identical to thepotential at the left and right reflectors 52 and 53 is applied to theassist electrode. Preferably, a voltage difference or a voltagefluctuation among the left reflector 52, right reflector 53 and theassist electrode 50 is retained within a range of ±100V. The assistelectrode 50 is formed with a conductive plate having an opening throughwhich a primary beam passes. The upper limit of detectable elevationangles at a generational position of a backscattering electron isrestricted by a size of an opening formed on the optical axis betweenthe left and right reflectors 52 and 53. Herein, when the edge of theopening of the assist electrode is tapered, an adverse effect of theassist electrode 50 on an electron beam (an electrostatic lens effect inthe opening) is reduced, so that the efficiency of focusing by theobjective lens is improved.

A secondary particle generated from irradiation of a primary beam isaccelerated upward (in a direction opposite to an incident direction ofa primary beam) by an electrode on the bottom of an objective lens. Inthe electron optical system shown in FIG. 5, a deceleration electricfield with respect to the Z direction is applied to the secondaryparticle that passed through the objective lens, by the assistelectrode. At this time, a velocity component of a backscatteringelectron propagating on an XY plane is not decelerated. Consequently, ahigh-angle component 56 of the backscattering electron sufficientlyspreads to lateral direction before reaching the opening between thereflectors, hence the trajectories of the low-angle and high-anglecomponents of the backscattering electron and secondary electrode areseparated from each other. Similarly, the trajectory of the low-anglecomponent of the backscattering electron spreads on the XY plane by theaffection of the deceleration electric field with respect to the Zdirection. Eventually, the low-angle component of the backscatteringelectron reaches to the reflectors in a condition separated from thehigh-angle component of the backscattering electron. On the other hand,the velocity component of the secondary electrode directed propagatingon the XY plane is so small that it hardly spread laterally beforereaching the opening between the reflectors.

Incidentally, the lateral spread of a backscattering electron can becontrolled by increasing or decreasing a Z-direction decelerationelectric field to be applied to a component of secondary particle thatpropagates in a Z direction. Consequently, the number of components of abackscattering electron that pass through the opening between thereflectors can be controlled by a voltage applied to the assistelectrode 50. Therefore, the installation of the assist electrode 50enables to control even a ratio of separation of the secondary electronand the backscattering electron each other. As mentioned above, in theelectron optical system shown in FIG. 5, the number of thebackscattering electron detected by the left detector 57 and rightdetector 58 increases by the lost amount of components since thecoincidence with the secondary electrons in the electron optical systemshown in FIG. 4. Thus, a shadow contrast is enhanced.

In the present example, although a pair of left and right reflectors 52and 53 is disposed symmetrically with respect to the optical axis of aprimary beam, the reflectors can be arranged in a way that the azimuthangle components are separated into two or more components. Further,although the description mentioned above is carried on a example wherethe objective lens is of magnetic/electrostatic compound objective lens,the principle is the same as that described so far even other type ofelectromagnetic lens is adopted.

According to the present invention, an image having a shadow contrastthereof enhanced can be produced during inspection of a semiconductordevice or the line having a circuit pattern. A shallow roughness can behighly sensitively detected.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, objects and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings wherein:

FIG. 1 is an explanatory diagram concerning a fundamental principle ofgeneration of a shadow image;

FIG. 2 shows the dependency of an emission concentration of a secondaryparticle on the energy of the secondary particle;

FIG. 3 shows the dependency of an rotational angle on an elevation angleat a generational position of a secondary particle;

FIG. 4 shows the trajectories of components of a secondary particle inan electron optical column including magnetic/electrostatic compoundobjective lens;

FIG. 5 shows the trajectories of components of a secondary particle inan electron optical column including an assist electrode;

FIG. 6 shows the internal configuration of an electron beam apparatus inaccordance with the first embodiment;

FIG. 7 shows the structure of a power control table relating to anassist electrode power supply and an objective-lens lower electrodecontrol power supply;

FIG. 8A and FIG. 8B show effects of an assist electrode;

FIG. 9 shows the internal configuration of an electron beam apparatus inaccordance with the second embodiment;

FIG. 10 shows the internal configuration of an electron beam apparatusin accordance with the third embodiment;

FIG. 11 shows a correlation among a range scanned with a primary beam, avoltage applied to an objective-lens lower electrode, and a degree ofcharging to which a sample is charged;

FIG. 12 shows the dependency of a shadow contrast-noise ratio on a slopeof a sample surface;

FIG. 13 shows the internal configuration of a scanning electronmicroscope included in a defect review apparatus in accordance with thefourth embodiment;

FIG. 14 shows the overall configuration of the defect review apparatusin accordance with the fourth embodiment;

FIG. 15A and FIG. 15B show the structures of a power control table and alens control table employed in the fourth embodiment; and

FIG. 16 shows the internal configuration of an electron beam apparatusin accordance with the fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

As the first embodiment, an adaptation to a scanning electron microscopewill be described below.

FIG. 6 shows the fundamental configuration of a charged-particle beamapparatus in accordance with the first embodiment. The charged-particlebeam apparatus in accordance with the present embodiment includes: anelectron optical system formed in a vacuum housing 125; an electronoptical system control apparatus 124 disposed in a peripheral of thecharged-particle beam apparatus; a host computer 121 that controlsindividual control units included in the control apparatus 124 andsupervises the entire charged-particle beam apparatus; an operatingconsole 122 connected to the control apparatus; and a display 123including a monitor on which an acquired image is displayed. Theelectron optical system control apparatus 124 includes a power supplyunit that feeds a current or a voltage to the elements constituting theelectron optical system, and signal control lines over which a controlsignal is transmitted to each of the elements.

The electron optical system includes: an electron gun 101 that generatesan electron beam (primary charged-particle beam) 100; a deflector 102that deflects the electron beam 100; immersion objective lens 103 thatconverges the electron beam 100; an assist electrode 106 that convergesor diverges a secondary particle emitted from a sample 104 retained on astage 105; a reflecting member to which the secondary particle collides;and a left detector 110, a right detector 111, and a center detector 112that detect an incidental (ternary) particle re-emitted due to thecollision. The assist electrode 106 is located approximately sameposition with the top of the immersion objective lens 103. Moreover, thereflecting member is divided into a lower reflecting member disposedbetween the objective lens 103 and a scan coil 102, and an upperreflecting member disposed between the electron gun 101 and scan coil102. The lower reflecting member is made of a conical metal member. In aconical surface of the conical metal member, a left collision surface107 and a right collision surface 108 to which a secondary particlecollides are formed. The upper reflecting member is made of a disk-likemetal member having a primary beam passage opening formed therein. Thebottom of the upper reflecting member constitutes a secondary particlereflecting surface 109.

The electron beam 100 emitted from the electron gun 101 is accelerateddue to a potential difference formed between a lead electrode and anacceleration electrode (which are not shown but are elements includingthe electron gun), and reaches the immersion objective lens 103. To thelower electrode included in the immersion objective lens 103, a voltagecausing a potential difference to the potential at the accelerationelectrode to be positive is applied. The electron beam 100 passes thelower electrode while being accelerated due to the potential differencebetween the acceleration electrode and the lower electrode. On the otherhand, a voltage causing a potential difference from the potential at thelower electrode to be negative is applied from a stage power supply 114to the stage 105. The electron beam 100 having passed the lowerelectrode is rapidly decelerated and reaches a sample surface as aprimary beam. Since a secondary particle generated from irradiation ofthe primary beam has a negative polarity, the secondary particle isaccelerated due to a potential difference between the sample surface andthe lower electrode, and reaches the top of the immersion objective lens103.

In the vicinity of the assist electrode 106, a deceleration electricfield that acts on a component of a secondary particle propagating in aZ direction is produced with a voltage applied from an assist electrodepower supply 115. Consequently, a high-velocity component(backscattering electron) contained in the secondary particle and passedthrough the assist electrode 106 is separated from a low-velocitycomponent contained in the secondary particle in its trajectory, andcollides to the left collision surface 107 and right collision surface108 of the reflecting member. To the left collision surface 107 andright collision surface 108, a voltage to generate an electric field forintroducing a ternary particle generated by collision of thehigh-velocity component of the secondary particle is supplied from aleft power supply 116 and a right power supply 117. Furthermore, avoltage to generate a electric field for the intake of the introducedbackscattering electron is supplied to the left detector 110 or rightdetector 111 from a left detector power supply 118 or a right detectorpower supply 119.

A secondary particle from which the backscattering electron (strictlyspeaking, a high-velocity component of a secondary particle) isseparated reaches the upper reflecting member, and collides to thesecondary particle collision surface 109 to generate a ternary particle.In a body of the center detector 112 disposed by the side of the upperreflecting member, a intaking electric field is induced by a centerdetector power supply 120. Under the strong electric field, a re-emittedternary particle is take fined into the detector.

Owing to the foregoing fundamental configuration, the left and rightdetectors enables to distinctively detect a high-elevation anglecomponent and a low-elevation angle component of the high-velocitycomponent, and enables to acquire a contrast enhanced shadow image.

Next, a method of controlling a voltage to be applied to the assistelectrode 106 will be described below. The scanning electron microscopein accordance with the present embodiment can be operated in twooperating modes, that is, in an operating mode (observation mode) ofdisplaying a roughness enhanced image of a sample surface, and anoperating mode (inspection mode) of displaying a contrast enhancedimage, of which the contrast is attributable to difference in thematerial of the sample surface.

On the display screen of the display 123, two selection buttons“Inspection Mode” and “Observation Mode” and a button “Discharge” aredisplayed. A user can select any of the buttons at the operating console122. Host computer 121 stores information of voltages to be applied tothe assist electrode 106 and the lower electrode of the objective lensrespectively in accordance with each of the operating modes. FIG. 7shows an instance of the configuration for controlling each of theoperation modes using a data table storing the voltages corresponding toeach operating mode. The data table shown in FIG. 7 is comprised of abeam mode selecting condition field in which index informationcorresponding to each operating mode is stored, and a voltage valuefield in which voltage values to be applied to the assist electrode 106and the lower electrode of the objective lens are stored. The beam modeselecting condition field is further divided into a major category fieldand a minor category field, and index information corresponding to the“inspection mode”, “observation mode” and a “normal mode” or a “chargemode” are stored. In the voltage value field, voltage values to beapplied to the assist electrode 106 and the objective-lens lowerelectrode corresponding to conditions configured to the combination ofthe index information stored in the major category field and minorcategory field.

When a user selects the Inspection Mode button, the host computer 121controls the transfer of signals in the electron optical system controlapparatus 124, and reads out a detection signal sent from the centerdetector 112. The host computer 121 includes an image processing unit,and uses the detection signal sent from the center detector 112 to forman image based on a low-velocity component of a secondary particle. Theformed image is displayed on the display 123. When the user selects theobservation mode, the host computer 121 reads a detection signal sentfrom the left detector 110 or right detector 111, executes imageformation, and displays an image based on a high-velocity component ofthe secondary particle. When the sample is charged, a luminance spot(shading) may appear in a displayed image. The shading occurs when thearrangement of an annular detector is deviated from the axially symmetrywith respect to the trajectory of a secondary particle. On the otherhand, in the configuration of the apparatus in accordance with thepresent embodiment, a secondary particle detector is disposed axiallysymmetrically with respect to the optical axis of a primary electronbeam in order to separate an azimuth component from the secondaryparticle. When a sample is charged, the axis of the trajectory of thesecondary particle may be relatively deviated from the center axis ofthe detector. On this occasion, the shading occurs.

When shading occurs, the operating modes of the apparatus are switchedto select the discharge mode. Thus, the shading can be removed. When theuser depresses the Discharge button, the voltages to be applied to theassist electrode 106 and the object-lens lower electrode arere-designated according to the table shown in FIG. 7. Consequently, asecondary particle detecting condition associated with the charged stateof a sample is established, and an image of the shading removed can beobtained.

The aforesaid configuration is the minimal configuration of acharged-particle beam apparatus in which the present embodiment isimplemented. For example, even when a condenser lens that helps focus anelectronic beam or a Faraday cup that measures a beam current isincluded, the constituent feature of the present embodiment can berealized. Moreover, the deflector generally falls into an electrostatictype and an electromagnetic type. When multiple azimuth components at agenerational position of a secondary particle from which the secondaryparticle is emitted are separated from each other, the left reflectorand right reflector may each be divided into multiple reflectors. Newdetectors may be included in association with the respective reflectors.

By providing a condenser lens between the electron gun 101 and secondaryparticle reflecting surface 109, the focus of an electron beam isimproved. Moreover, by employing two condenser lenses in two stage andproviding an aperture for limiting a beam current in the two condenserlenses, the beam current and an aperture angle at the objective lens canbe controlled independently, helping the focus of the electron beam.

FIG. 8A and FIG. 8B show energy distributions of elevation-anglecomponents of a secondary particle detected by the left detector 110 incomparison with a presence of the assist electrode and an absence of theassist electrode. In the graphs, the vertical axis indicates theelevation angles exhibited by the elevation-angle component of asecondary particle collided to the left reflector, ranging from 0° to90°. The horizontal axis indicates the energy of a secondary electronranging from 0 to the same level of the energy of an primary electronbeam (Vp). In the graphs, a portion hatched with dots indicates a domainrepresenting a component of a secondary particle that collides to theleft reflector. A portion hatched with stripes indicates a domain ofenergy representing a low-velocity component of the secondary particletermed in the present embodiment. V_(CF) denotes the lowest energyexhibited by a high-velocity component of the secondary particle.

In a case of an absent of an assist electrode (FIG. 8A), the lowestenergy V_(CF) exists within a low-velocity component domain. Thissignifies that a low-energy component of a secondary particle isdetected by the lower detector, which should be detected by the upperdetector. On the other hand, in a case of an presence of the assistelectrode (FIG. 8B), the lowest energy V_(CF) exists away from thelow-velocity component domain. This signifies that a low-velocitycomponent is not mixed in a component of the secondary particle detectedby the lower detector.

The configuration described in the present embodiment realizes anelectron optical system, in which a degree of separation of ahigh-velocity component of a secondary particle and a low-velocitycomponent is improved compared to conventional electron optical system.The advantage is especially remarkable in a case where the electronoptical system is adapted to a defect inspection apparatus or a criticaldimension measurement apparatus utilizing a scanning electronmicroscope.

Second Embodiment

FIG. 9 shows the fundamental configuration of a charged-particle beamapparatus in accordance with the second embodiment. The charged-particlebeam apparatus in accordance with the present embodiment has aconfiguration devoid of a reflecting member, and is intended to realizethe same constituent feature as that of the configuration described inrelation to the first embodiment despite a simpler configuration. Thecomponents of the apparatus will be described in conjunction with FIG.9. However, as to the components whose operation, function, orarrangement are identical to those of the components included in thefirst embodiment, the explanation is omitted.

The charged-particle beam apparatus in accordance with the presentembodiment includes an electron optical system formed in a vacuumhousing 170, an electron optical system control apparatus 169, a hostcomputer 166 that supervises the entire apparatus, an operating console167 connected to the control apparatus, a display 168 including amonitor on which an acquired image is displayed, and a stage 155. Theelectron optical system control apparatus 169 includes a power supplyunit that feeds a current or a voltage the elements constituting theelectron optical system, and signal control lines over which a controlsignal is transmitted to each of the elements. The electron opticalsystem includes an electron gun 151 that produces an electron beam 150,a scan coil 152 that sweeps an electron beam over a sample 154,immersion objective lens 153, an assist electrode 156 that focuses ordisperses a secondary particle which is emitted from the sample 154, anda left detector 157, a right detector 158, and a center detector 159 towhich a secondary particle collides.

The immersion objective lens 153 includes magnetic poles to be used toleak a magnetic field along the optical axis of a primary beam, anexcitation coil for inducing a magnetic field around the magnetic poles,and a lower electrode disposed on the bottom of the objective lens. Avoltage is applied from an electrode power supply 160 to the lowerelectrode. Due to an electric field induced with the application, anelectron beam 150 and a secondary particle are accelerated. A retardingvoltage is applied from a stage power supply 161 to the stage 155. Thesecondary particle is accelerated by the voltage. An assist electrodepower supply 162 feeds a voltage, which is used to induce abackscattering electron deceleration electric field, to the assistelectrode 156. A left detector power supply 163, a right detector powersupply 164, and a center detector power supply 165 are used to take in asecondary particle to the left detector 157, right detector 158, andcenter detector 159 respectively. Since the apparatus in accordance withthe present embodiment does not include a reflecting member, theapparatus is devoid of the left collision surface 107 and rightcollision surface 108 that are included in the apparatus in accordancewith the first embodiment. Therefore, the potentials at the leftdetector 157 and right detector 158 get relatively higher than those inthe apparatus in accordance with the first embodiment. Consequently, theabsolute value of the potential at the assist electrode 156 has to behigher than that in the apparatus in accordance with the firstembodiment.

Owing to the foregoing fundamental configuration, the left detector andright detector make it possible to selectively detect a velocitycomponent of a secondary particle and an azimuth component thereof at agenerational position at or from which the secondary particle isgenerated or emitted, and to acquire a shadow image having a contrastthereof enhanced.

The fundamental configuration is the minimal configuration of acharged-particle beam apparatus in which the present embodiment isimplemented. For example, even when a condenser lens that helps focus anelectron beam or a Faraday cup that measures a beam current is included,the constituent feature of the present embodiment can be realized. Asfor the deflector, an electrostatic type is easier to use than anelectromagnetic type is. Since the electrostatic type is compact andlittle affects the trajectory of a secondary particle, the detectors canbe easily disposed on the side of the electron gun on which there ismuch room. In order to detect or select multiple azimuth components of asecondary particle at the generational position of the secondaryparticle, each of the left detector and right detector may be dividedinto multiple detectors.

Third Embodiment

FIG. 10 shows the fundamental configuration of a charged-particle beamapparatus in accordance with the third embodiment of the presentinvention. The charged-particle beam apparatus in accordance with thepresent invention includes, in addition to a reflecting member, an ExBdeflector. As a trajectory separating means of a secondary electron fromthe trajectory of a backscattering electron, magnetic poles aresubstituted for the assist electrode. Referring to FIG. 10, thecomponents of the apparatus will be described below. However, adescription of the components whose actions, capabilities, ordispositions are identical to those of the components included in thefirst embodiment will be omitted.

The charged-particle beam apparatus in accordance with the presentembodiment includes an electron optical system formed in a vacuumhousing 225, an electron optical system control apparatus 224, a hostcomputer 221 that controls the whole of the apparatus on a centralizedmanner, an operating console 222 connected to the control apparatus, adisplay 223 including a monitor on which an acquired image is displayed,and a stage 205. The electron optical system control apparatus 224includes a power supply unit that feeds a current or a voltage to theelements constituting the electron optical system, and signal controllines over which a control signal is transmitted to each of theelements. The electron optical system includes: an electron gun 201 thatproduces a primary electron beam 200; an ExB deflector (Wien filter) 202that separates a secondary particle, which is generated from irradiationof a primary beam, from the primary beam; immersion objective lens 203;an assistant magnetic field application device 206 interposed betweenthe lower electrode of the immersion objective lens 203 and the ExBdeflector 202; a first-stage reflecting member including a leftcollision surface 207 and a right collision surface 208 to which asecondary particle collides; a lower detector including a left detector210 and a right detector 211 that detect a ternary particle which isgenerated by the secondary particle colliding to the reflecting member;a second-stage reflecting member 209 interposed between the first-stagereflecting member and electron gun; and an upper detector 212.Incidentally, the electron optical system shown in FIG. 10 includes ascan coil that sweeps a primary beam 200, even though the scan coil isnot shown.

Power to be used to induce a ternary particle introduction electricfield is fed from a left power supply 216 and a right power supply 217to the left collision surface 207 and right collision surface 208 of thefirst-stage reflecting member respectively. To the upper detector andlower detector, power for forming an electric field used to take in aternary particle is fed from a left detector power supply 218, a rightdetector power supply 219, and a center detector power supply 220respectively.

Power to be used to induce an acceleration electric field under whichthe electronic beam 200 and a secondary particle are accelerated is fedfrom an electrode power supply 213 to the lower electrode of theimmersion objective lens 203. Power to be used to induce a retardingelectric field is fed from a stage power supply 214 to the stage 205.

The assistant magnetic field application apparatus 206 includes magneticpoles made of a soft magnetic material and a coil. An excitation currentthat flows through the coil is fed from an assistant magnetic fieldpower supply 215. A backscattering electron is bent using a magneticfield induced around the right and left magnetic poles, whereby thetrajectory of the backscattering electron is separated from that of asecondary electron. The employment of the magnetic field makes itpossible to directly accelerate a velocity component propagating on anXY plane. Consequently, separation from the trajectory of the secondaryelectron can be achieved efficiently.

Owing to the fundamental configuration, the left detector 210 and rightdetector 211 make it possible to selectively detect a velocity componentand an azimuth component at a generational position at or from which asecondary particle is generated or emitted, and to acquire a shadowimage having a contrast thereof enhanced.

Fourth Embodiment

The present embodiment will be described by taking the configuration ofa defect review inspection apparatus for instance. Many defect reviewapparatuses have a drawback that shading stems from charging of asample. In relation to the present embodiment, a cause of shading willbe described first.

To begin with, referring to FIG. 11, the relationship between chargingof a sample and shading will be described. FIG. 11 shows a degree ofcharging in a situation that an insulating sample is irradiated with anelectron beam having a beam current retained at a certain value. Thevertical axis indicates values of a voltage Vb (kV) applied to the lowerelectrode included in the immersion objective lens, and the horizontalaxis indicates a length FOV (μm) of a range to be scanned with anelectron beam. The degree of charging is indicated with a heightrepresented by a contour line 93. In the immersion objective lens, thehigher an electrode voltage is, the higher a resolution is obtained,however, the degree of charging increases. As the degree of chargingincreases, a drawback such as destruction of a sample or shadingattributable to a shift of the trajectory of a secondary electron takesplace. In order to avoid the drawback, it is necessary to appropriatelycontrol an electrode voltage in the immersion objective lens. Along witha change in the electrode voltage in the objective lens, the trajectoryof a secondary electron changes from one to another. In order to preventa contrast of a shadow image from being degraded, trajectory separatingmeans have to be controlled at the same time when the electrode voltagein the objective lens is controlled.

Referring to FIG. 12, an elevation-angle component required for fearthat a contrast of a shadow image may be degraded will be qualitativelydescribed below. FIG. 12 shows the dependency of a shadow contrast on aslope. The vertical axis indicates normalized shadow contrast values,that is, a normalized intensity of a shadow contrast between a portionof a slope 5 (FIG. 1) in a sample surface and a flat portion of thesample surface, which is normalized with a value of noise contained inan electron beam image on the observation. The horizontal axis indicatesthe values of the slope 5 of the sample surface at a generationalposition due to the roughness caused by a foreign matter or as such. Alegend 70 presents detectable upper limits of elevation angles at agenerational position at which a backscattering electron is generated. Acurve 71 that the upper limit is more than or equal 70° indicatesrelatively stronger shadow contrast than the other curves that the upperlimits is less than 70°. On the other hand, the curves that the upperlimits is equal to or larger than 70° are nearly coincidence with eachother throughout the entire range of the graph. Consequently, bydetecting the remaining 70° to 0° elevation-angle component of thebackscattering electron, a qualified shadow contrast substantiallyequivalent to an ideal shadow contrast obtained in a situation that allthe components of the backscattering electron are distinguished intoright-side components and left-side components, even though thetrajectories of the 90° to 70° elevation-angle component of abackscattering electron are coincidence to the trajectory of a secondaryelectron.

Next, referring to FIG. 13 and FIG. 14, the internal elementsconstituting an electron optical system of a defect review inspectionapparatus in accordance with the present embodiment and the overallconfiguration of the apparatus are explained. The charged-particle beamapparatus in accordance with the present embodiment includes: anelectron optical system formed in a vacuum housing 328; an electronoptical system control apparatus 327 disposed on the periphery of thehousing; an information processing apparatus 324 that controls controlunits and a power unit included in the electron optical system controlapparatus 327 and that controls the whole of the apparatus on acentralized manner; an operating console 325 connected to the controlapparatus; a display 326 including a monitor on which an acquired imageis displayed; and a stage 305 on which a sample 304 is retained. Theelectron optical system control apparatus 327 includes the power unitthat feeds a current or a voltage to the elements of the electronoptical system, and signal control lines over which a control signal istransmitted to each of the elements.

The electron optical system includes: an electron gun 301 that producesa primary electron beam 300; an ExB deflector (Wien filter) 302 thatseparates a secondary particle, which is generated from irradiation ofthe primary beam, from the primary beam; immersion objective lens 303that focuses an electron beam 300; an assist electrode 306 located at aposition nearly squared with the top of the immersion objective lens303; a first reflecting member to which a secondary particle collides; aleft detector 310 and a right detector 311 that detect an incidental(ternary) particle re-emitted due to the collision; a second reflectingmember 309 located above the first reflecting member (on the side of anelectron source); a center detector 312 that detects an incidental(ternary) particle produced from the secondary particle which hascollided to the second reflecting member; a first condenser lens 313, asecond condenser lens 314, a beam limiting aperture 315, a stigmator329, and an aligner 330; a voltage feeding power supply 316 from which avoltage is applied to the lower electrode of the immersion objectivelens 303; a retarding power supply 317 from which a retarding voltage isapplied to the sample stage; an assist electrode power supply 318; aleft power supply 319 and a right power supply 320 from which power tobe used to induce a secondary particle introduction electric field isfed to the respective detectors; and a left detector power supply 321, aright detector power supply 322, and a center detector power supply 323.As the electron gun, a Schottky-type electron source, a cold fieldemission type electron source, or a thermoelectron emission typeelectron source may be adopted. The first reflecting member is formedwith a conical metal member. On the conical surface of the firstreflecting member, a left collision surface 307 and a right collisionsurface 308 to which a secondary particle collides are formed. Thesecond reflecting member is formed with a disk-like metal member havingan opening, through which a primary beam passes, formed therein, and thebottom surface of the second reflecting member constitutes a secondparticle reflecting surface 309. The reflecting member may be dividedinto multiple reflecting members, and detectors may be associated withthe respective reflecting members. In this case, azimuth anglecomponents of a secondary particle can be more finely discriminated fromone another. Moreover, by employing the first condenser lens 313, secondcondenser lens 314, and beam limiting aperture 315, the control of thebeam current is ensured. In the present embodiment, since the ExBdeflector (Wien filter) 302 is included, a secondary particle can beefficiently collected. Further, by employing the beam limiting aperture315 between the first condenser lens 313 and second condenser lens 314,the beam current and the spread of the primary electron beam 300 at theimmersion objective lens 303 can be controlled independently of eachother. Consequently, compared with the apparatuses of the otherembodiments, the apparatus in accordance with the present embodiment canmost efficiently focus the primary electron beam 300 in any range of thebeam current.

FIG. 14 shows the overall configuration of a defect review system towhich the present embodiment is adapted. The defect review system towhich the present embodiment is adapted includes, in addition to theinformation processing apparatus 324 and a display 326, an electronoptical column 351 that irradiates a charged-particle beam to a samplesubstrate that is a sample to be inspected and detects asecondary-particle signal or a two-dimensional intensity distributionbased on the secondary-particle signal, a main chamber in which samplesubstrates are stored, a load-lock chamber 352 used to carry each samplesubstrate into or out of the main member, a sample substrate casing inwhich each sample substrate is stored, and a robot 353 that transportseach sample substrate from the sample substrate casing to the load-lockmember. Thus, the sample substrates in the main member can beautomatically exchanged.

A control apparatus 500 includes functional units, such as; a displaycontrol unit 501, an electron microscope control unit 502 that controlsthe components of the electron microscope, and a display datacomputation unit 503 that computes various display data items to behandled by the display control unit 501.

The electron microscope control unit 502 further includes suchfunctional blocks as a beam sweep control block, a column control block,a stage control block, a vacuum pump control block, and a robot controlblock. The beam sweep control block controls sweeping of a beam by theelectron optical column and acquires a signal. Moreover, the beam sweepcontrol block, column control block, and stage control block executetheir control sequences synchronously with one another until the controlsequences end with completion of inspection. The display datacomputation unit 503 includes: a recipe control block that runs agraphical user interface (GUI) for a recipe screen image; an imageprocessing block that performs computations including image comparisonand image analysis so as to execute formation of a high-resolutionobservation image expressing a defect, extraction of a defect or aforeign matter, classification of a defect, or any other inspectionalprocessing; and a defect coordinate control block that determines aposition, to which a primary electron beam is irradiated, on the basisof defect position data which is obtained through defect coordinatesampling performed by the image processing block or which is receivedfrom any other inspection apparatus, and transmits the position to thestage control block. The above functional blocks are implemented byprocessor included in the control apparatus 500, software run by theinformation processing means, memory in which the software is stored,means for issuing a control instruction, and means for receiving asignal.

An operator registers an inspection recipe of the inspection system tothe recipe control block via the display control unit. Based on theinspection recipe, the recipe control block communicates at a high speedwith the display control unit, image processing block, defect coordinatecontrol block, beam sweep control block, column control block, stagecontrol block, vacuum pump control block, and robot control block. Thebeam scan control block, column control block, stage control block,vacuum pump control block, and robot control block communicates acontrol signal and other signals to or from a charged-particle beamcontrol apparatus. On the display screen of the display means 326, aformed image, an observational magnification selection button, a beammode selection button, an inspection recipe, a result of classificationof a defect, and other information are displayed. This enables theoperator to select an observational magnification and a beam mode. Here,the “beam mode” means an irradiation condition of a primary electronbeam in an inspection mode or an observation mode (to be describedlater), or in a normal mode or a discharge mode accompanying theinspection mode or the observation mode. Moreover, the inspection recipeis appropriately selected or constructed according to a purpose of aninspection. FIG. 14 shows an example in which a defect map displaybutton, a detection mode/observation mode switching button, and aclassification map display button are displayed on the display screen asa ticker for designating the inspection recipe. Herein, the detectionmode and observation mode refer to an operating mode of the electronoptical column in acquiring an observation image utilized for detectinga defect or a foreign matter, and an operating mode of the electronoptical column in acquiring a finer observation image of the defect orforeign matter. Consequently, the operator can easily designate aninspection recipe and register the designated inspection recipe in therecipe control block. Moreover, the result of classification of a defectis displayed on the display screen so that the operator can collate adisplayed defect image with the result of classification.

After the completion of the inspection based on the inspection recipe,the sample substrate is transported to the load-lock member, and carriedout of the load-lock member and put in the casing by the robot. Ifnecessary, transportation of the next sample substrate is initiated. Theinspection recipe, observation image data, and result of classificationare stored in the memory included in the information processingapparatus 324, and provided as inspection data whenever it is needed.

FIG. 15A shows a power control table specifying power control valuescorresponding to the elements of the electron optical system in each ofthe beam modes. Herein, the power values Vst, Vb, Vc, Vre, and Vsc arevoltage values fed from the retarding power supply 317 (Vst), lowerelectrode power supply 316 (Vb), assist electrode power supply 318 (Vc),right and left reflecting member power supplies 320 and 319 (Vre), rightand left detector power supplies 322 and 321 (Vsc), and center detectorpower supply 323 (Vsc), respectively. The power control table is storedin the information processing apparatus 324. When the operator selects abeam mode by manipulating the beam mode selection button displayed onthe screen or the operating console 325, the computing means included inthe information processing apparatus 324 refers the power control tableand reads out the associated power control values. The read out controlvoltage values are transmitted to the electron optical system controlapparatus 327. The power supplies are controlled based on the controlvoltage values. In a case of severe charging, the charge mode isselected. Particularly, low-magnification observation (a magnificationin a situation that a scan range exceeds about 10 μl or more) in theinspection mode, a charging voltage is likely to get higher than that inthe observation mode. The charge mode is therefore often adopted.

FIG. 15B shows a lens setting table in which lens setting values of theelectron optical system corresponding to each of the beam modes arestored. Similarly to the power control table, the lens setting table isstored in the memory included in the information processing apparatus324. When the beam modes are switched, the computing means refers thelens setting table and reads out control current values for theobjective lens, stigmator, and aligner respectively. In a discharge modeutilized in an occurrence of the shading, setting values are selected ina manner that the potential difference between the voltages Vst and Vband the potential difference between the voltages Vc and Vre aredecreased. The read out control current values are transferred to theelectron optical system control apparatus 327, then the elementsconstituting the electron optical system are controlled.

As mentioned above, according to the defect review apparatus of thepresent embodiment, a shadow contrast enhanced image can be acquired inthe inspection of a semiconductor device having a circuit pattern or thelike. A shallow roughness attributable to the very tiny foreign matteror the like can be detected with high sensitively. Consequently, thenumber of integration times of an image data for the assurance of imagequality is decreased. Eventually, fast defect detection and defectreview are realized without degradation of precision in defectdetection. Further, the precision in defect classification improves, anda cause of a defect can be identified readily.

Although the present embodiment has been described on an instance of thedefect review apparatus employing an electron beam, adaptation to ageneral charged-particle beam apparatus employing a charged-particlebeam such as an ion beam is also effective.

Fifth Embodiment

As the present invention, a variant of the electron optical system shownin FIG. 13 will be described below. FIG. 16 shows the fundamentalconfiguration of a charged-particle beam apparatus in accordance withthe fifth embodiment. A description of the capabilities or actionsshared by the components shown in FIG. 13 will be omitted.

The charged-particle beam apparatus in accordance with the presentembodiment includes: an electron gun 401 that produces an electron beam400; a deflector 402 that deflects the electron beam 400; a firstcondenser lens 421, a second condenser lens 422, and immersion objectivelens 403 that focus the electron beam 400; a stage 405 that moves asample 404; an assist electrode 406 that focuses or disperses asecondary electron which is emitted from the sample 404; a leftreflector 407, a right reflector 408, and a center reflector 409 towhich a secondary electron collides; a left detector 410, a rightdetector 411, and a center detector 412 that detect a secondary electronre-emitted due to the collision; and a first condenser lens 421 and asecond condenser lens 422.

In the immersion objective lens 403, the electron beam 400 and asecondary electron are accelerated by an electrode power supply 413. Onthe stage 405, the electron beam 400 is decelerated by a stage powersupply 414 and the secondary electron is accelerated owing thereby. Theassist electrode 406 focuses or disperses the secondary electron owingto an assist electrode power supply 415. The left reflector 407introduces the secondary electron, which is re-emitted, to the leftdetector 410 owing to a left power supply 416. The right reflector 408introduces the secondary electron to the right detector 411 owing to aright power supply 417. The left detector 410, right detector 411, andcenter detector 412 take in the secondary electron, which is re-emitted,using an intense electric field induced by a left detector power supply418, a right detector power supply 419, and a center detector powersupply 420 respectively.

Owing to the foregoing fundamental configuration, the left detector andright detector make it possible to selectively detect a velocitycomponent of a secondary electron and an azimuth component thereof at agenerational position at which the secondary electron is generated, andto acquire a shadow image whose contrast is enhanced. In the presentembodiment, the center reflector 409 is interposed between the firstcondenser lens 421 and second condenser lens 422, and used as a beamlimiting aperture for control of a beam current. Consequently, thenumber of microscopic holes through which the electron beam 400 passescan be decremented by one. The primary electron beam 300 can be mostefficiently focused irrespective of a beam current.

1. An electron beam apparatus including an information processingapparatus, a display, an electron optical column that irradiates acharged-particle beam to a sample substrate which is a sample to beinspected and detects a secondary-particle signal or a two-dimensionalintensity distribution based on the secondary-particle signal, a mainchamber in which sample substrates are stored, a load-lock chamber usedto carry each sample substrate into or out of the main chamber, and arobot which transports each sample substrate to the load-lock chamberand can automatically exchange the sample substrates: the informationprocessing apparatus comprising: a display control unit; an electronmicroscope control unit which has a beam scan control block, a columncontrol block, a stage control block, a pump control block and a robotcontrol block; and a display data computation unit which has a recipecontrol block, a image processing block and a defect coordinate controlblock; wherein the recipe control block communicates at a high speedwith the display control unit, the image processing block, the defectcoordinate control block, the beam scan control block, the columncontrol block, the stage control block, the pump control block and therobot control block based on an inspection recipe registered via thedisplay control unit; and wherein the display has a screen fordisplaying and selecting a defect map, a classification map, a formedimage, an observational magnification, an inspection mode which refersto an operating mode of the electron optical column in acquiring anobservation image utilized for detecting a defect or a foreign matter,an observation mode which refers to an operating mode of the electionoptical column in acquiring a finer observation image of the defect orforeign matter, a normal mode or a charge mode which accompanies theinspection mode or the observation mode and is an irradiation conditionof a primary electron beam, and displays a result of classification of adefect.
 2. The electron beam apparatus according to claim 1, wherein therecipe control block comprises a beam mode selecting field in whichindex information corresponding to each operating mode is stored, avoltage value field in which voltage values to be applied to an assistelectrode and a lower electrode of an objective lens are stored, whereinthe beam mode selecting field is further divided into a major categoryfield and a minor category field, and index information corresponding tothe “inspection mode”, “observation mode” and a “normal mode” or a“charge mode” are stored, and the voltage value field stores voltagevalues to be applied to the assist electrode and the lower electrode ofthe objective lens corresponding to conditions configured to acombination of the index information stored in a major category fieldand a minor category field.